Steam-boiler



(NoModeL) E. H. ASHCROFT.

Steam Boiler. No. 240,219. Patented April 19,1881.

NPETERS. PHOTO-LITHOGRAPHER. WASHINGTON. u c.

\ UNITED STATES PATENT OFFICE.

EDWARD H. ASHCROFT, OF LYNN, MASSACHUSETTS.

STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 240,219, dated April19, 1881.

Application filed February 26, 1881. (No model.)

To all whom it may concern Be it known that I, EDWARD H. ASHCROFT, acitizen of the United States, residing at Lynn, in the county of Essexand State of Massachusetts, have invented a new and useful Improvementin Steam-Boilers; and I do hereby declare that the following is a full,clear, and exact description thereof, reference being had to theaccompanying drawings, forming a part of this specification, in which-Figure 1 is an elevation, partly in section; Fig. 2, a plan view of thecentral nozzle; Fig. 3, a plan View of an end nozzle when applied asrepresented in Fig. 1; and Fig. 4 an elevation, partly in section, of amodified arrangement of my invention.

Similar letters of reference indicate correspondin g parts in theseveral figures.

This invention relates to steam-boilers of the compound type which arecomposed of two parts, one containing the internal tubes or flues andconstituting the principal generator, and the other or auxiliary partserving as the water and steam chamber from which the supply of steam isdrawn. These respective parts are usually constructed of independentcylindrical shells, arranged one above the other and connected togetherby intermediate nozzles, which form communicating passages, theauxiliary part being placed above the generator and covered with a hood,within which the escaping products of combustion are contained, whichprevents a loss of heat by radiation and also superheats the steam.

In the construction of this type of boiler it has been found difficultto apply the intermediate nozzles particularly at the extreme ends ofthe respective shells, where it is desirable to place the opening orpassage as near as pos sible to insure unobstructed circulation.Heretofore these nozzles have been formed by turning up or flanging apart of the plate of each shell, and lapping and riveting the sametogether. This expedient not only necessitated an abrupt bending of theplates, butin forming a flange-connection with the ends or heads incontact unshapely bends and unsightly seams were presented.

The object of this invention is to overcome this difficulty, and also toprovide in the construction of the nozzles means for retaining a part ofthe water in the auxiliary chamber at all times, all as hereinafterparticularly described and claimed.

In the drawings, a represents the main portion of the boiler, and b theauxiliary water and steam chamber.

c c are the connecting-nozzles, which embody my invention. Thesenozzles, owing to their limited length, are necessarily of such shape toconform to the adjacent parts that it is deemed preferable to constructthem of cast metal, thereby lessening the cost of manufacture, securinggreater strength, in the more rigid support, and in avoiding theweakening effect in the bending and fitting of wroughtplates.

The nozzle 0, which is designed to be used at the middle portion of theboiler, is composed of a central tube, d, forming the passage, which isfitted within circular openings in the shells of the respective parts,the bottom or lower end of said tube being flush with the interiorsurface of the shell, and the upper end extending beyond the interiorsurface of the shell of the auxiliary chamber, whereby an amount ofwater in depth equal to the distance said tube extends within thechamber will be retained therein, the projecting tubes not permitting areturn of all the water when the level falls below the chamber. Thistube is provided with circumferential flanges 0, formed to fit theexterior shape of the respective shell, and to which they are secured byriveting or in any well-known way. One or more of these intermediatenozzles may be used, as judgment may dictate, to accommodate boilers ofvarying length, or to increase or diminish the capacity of the aggregatepassages.

Themozzlcs c, which are placed at the 8X- treme ends of the respectiveparts, are essentially the same as a half-section of the inter mediatenozzles, c, the flat side being arranged in contact with the end orhead, and slots provided between the central tube and the exteriorprojecting flanges to receive the end flanges, this construction formingan uninterrupted connection or seam and securing the open passage at theextreme end of the boiler, whereby no obstruction is interposed to thefree circulation at this point.

In a modification of this invention, Fig. 4,1

have shown the complete circular nozzles located as near the ends as itmay be found convenient and practical, and supplemen tary tubes hinserted between the same and the extreme ends of the boiler, wherebythe same result may, in a measure, be accomplished, this modificationbeing also adapted to a construction in which the respective heads ofeach part of the boiler are made in separate and distinct parts, thefirst-described construction permitting the head to cover each partto beapplied in a single plate.

The advantages resultingfrom this construction are manifestly superiorin regard to strength, durability, and appearance when compared with theuse of wrought plates, and the cost of manufacture is greatly reduced.

EDWARD H. ASHCROFT.

\Nitnesses F. T. TAPLEY, J. M. CLARK.

